Sash-balance.



Nu. 68l,864. Patented Sept. 3, IBM.

.1. H. WA LACE & A. a. HILTON. SASH BALANCE.

(Application filed June 7, 1900.) N 0 M o d e l WI Z'NE 55.25. I M YENTHEE. w

7? @WWg? jwrrnn STATES PATENT OFFICE.

JAMES H. \VALLACE AND ARTHUR G. HILTON, OF PROVIDENCE, RIIODE ISLAND,ASSIGNORS TO THE INTERNATIONAL BURGLAR PROOF SASH- BALANCE AND LOOKCOMPANY, INCORPORATED, OF SAME PLACE.

SASH-BALANCE.

SPECIFICATION forming part Of Letters Patent No. 681 ,864.-, dated.September 3, 1901.

Application filed June '7, 1900- .To (ZZZ whom it may concern.-

Be it known that we, JAMEs H. WALLACE and ARTHUR G. HILTON,citizens ofthe United States,residing at Providence,in the county of Providence andState of Rhode Island, have invented a new and useful Improvement inSprings and Cases for Sash-Balances, of which the following is aspecification.

In window-sash balances and other devices '10 used in the artshelically-coiled springs are used to impart rotary motion when requiredto the case or to the spindle. The ends of these coiled springs areusually connected one end to the central spindle and the other I 5 endto the peripheral wall of the case. When the ends are permanentlysecured, the m0- mentum exerted by the unwinding of the spring is liableto carry the moving part beyond the point where the coiled spring exertsthe power and the spring near the point Where it is secured is liable tobend and become weakened or broken.

The object of this invention is to provide a casing and construct acoiled spring so that z 5 the spring is free to turn in the case, butwill be held as soon and as long as the tension of the spring isresisted.

The invention consists in the peculiar and novel construction of thecase and the ends 0 of the spring, whereby the spring will automaticallyconnect with the case when strain is applied, as will he more fully setforth hereinafter.

Figure 1 is a sectional view of the case and 5 the spring, showing theconnection of the ends of the coiled spring with the case. Fig. 2 is asectional view of the case and the coiled spring, illustrating theaction of the arm at the outer end of the coiled spring when strain isexerted on the spring.

In the drawings, a indicates the peripheral wall of the case; a, theinwardly-curved enlargement of the peripheral wall of the case formingthe abutment a against which the outer end of the spring bears; b, thecentral post or shaft, and b the helical surface on the same,terminating in the abutment 19 The helically-coiled spring 0 is formedof a flat steel band. The inner end 0 of the steel Serial No. 19,402.(No'modaL) band forming the coiled spring is bent to form a U -shapedhook. The end of the spring forms one arm of the U-shaped hook. Theouter part near the end of the coiled spring a is abruptly bent at 0 theend of the springblade forming the arm 0 which has in the preferred forma length of about one-third the inner diameter of the case and in thepreferred form is made somewhat thicker than the rest of thespring-blade. The U- shaped hook o is preferably made as rigid aspossible, so as to practically retain its shape under any strain thespring may be subjected to, while the bend is made as flexible aspossible, so that the arm 0 integral with the spring 0, as shown in Fig.1, may act in the same manner as the arm 0 pivotally secured at 0 shownin Fig. 2, and indicated in broken lines bearing against the coiledspring.

we will now more fully describe the operation of the coiled spring withrelation to the case.

When applied to a window-sash balance the peripheral wall a will form asupport of a gear and the post I) will be stationary and fixed in theframe, the case revolving around the post I). The case is usuallysupported in the frame of the window, the gear engaging with a rack onthe sash. WVhen the sash is lowered, the case revolves in the directionindicated by the arrow shown in Fig. 2, thereby winding up the coiledspring and increasing the tension on the same. When the sash is raised,the case revolves in the direction opposite to the direction indicatedby the arrow and the coiled spring unwinds and follows the case untilthe tension of the springis expended, and if the case is rotated beyondthis point the U -shaped hook c of the spring may slide around the postI) or the arm a slide along the inner surface of the peripheral wall aand pass 0 one or more of the curved enlargements,if more than one isused, as is shown in Fig. 2. As soon as the rotation of the case isreversed the hook 0' will engage with the abutment or one of theabutments b and the arm 0 with the 5 abutment or one of the abutments a0n the inner surface of the case. In Fig. 2 three abutments a on thecase and two abutments b on the post are shown. If the coiled spring isused in a stationary case and the post I) is to be rotated, the post bbecomes the central shaft, which may be rotated to wind up the spring orrotated by the spring without permanently securing the same with thepost or shaft or with the case and without the risk of breaking orinjuring the spring. In practice we find that the hook c to reliablyengage with the abutment should have the limb of the U formed by the endof the spring practically parallel with the other limb, so

as to bear fairly on the abutment and prevent the straightening out ofthe hook.

Having thus described our invention, we claim as new and desire tosecure by Letters Patent- 1. In a mechanism operated by ahelicallycoiled spring, the combination with the case inclosing thespring, the central post and an abutment on the central post, of anabutment formed by the inward extension of the curved inner surface ofthe case, and a helical spring having its inner end formed into aU-shaped hook and its outer end bent backward to form an arm longer thanthe distance between the inner surface of the case and the coil of thespring when said spring is wound up or contracted, whereby a springdisconnected from the case may engage with the abutments, as described.4 a

2. In a sash-balance or similar device, a

spring-case having an inward-extendin g abut Inent formed by the inwardextension of the curved inner surface of the case, in combination with aspring having an arm at its outer end of a length greater than the spacebetween the outer coil of the spring and the inner face of the case whensaid spring is wound up or contracted, whereby the case may rotateunrestrained by the spring in one direction and is restrained whenrotating in the opposite direction, as described.

3. In a sash-balance ,or similar device, a 1'0- tatable spring-casehaving two or more inward-extending abutments formed by the inwardcurving of the inner surface of the case, and a central fixed postprovided with two abutments in combination with a helicallywound springloose in the case and provided at the inner end with a U-shaped hook andat the outer end with an arm of a length greater than the distancebetween the outer coil of the spring and the inner surface of the casewhen said spring is wound up or con tracted, as described.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

JAMES H. WALLACE. ARTHUR G. HILTON.- Witnesses:

B. M. SIMMs, J. A. MILLER, J r.-

